1. Field of the Invention
The present invention relates to an information recording method and apparatus therefor, and more particularly to a method and apparatus for recording an information on a magnetic track on a photographic negative film by supplying a magnetic head with a signal corresponding to the information to be magnetically recorded on the magnetic track.
2. Related Art
PCT Application Laid-Open No. 4-502518 discloses that a magnetic recording section including so-called camera tracks and so-called processing laboratory tracks is formed by applying a transparent magnetic substance to a photographic negative film, and an information regarding a negative film and an information regarding images recorded on the negative film are recorded on the camera tracks and the laboratory tracks. According to this PCT application, an information regarding an image can be recorded on the magnetic recording section at a location physically corresponding to the location of a corresponding image frame in which the image is recorded, so that the information can be searched quite easily. On the camera tracks of the magnetic recording section, the date and time of photographing, the place of photographing, the conditions for photographing, and the like can be recorded for each image when the photographic negative film is rewound after completion of the photographing. In a processing laboratory, each image on a frame is tested or collated by a photographic negative film tester or a collating apparatus to record a compensation value for exposure conditions on the processing laboratory tracks of the magnetic recording section. Moreover, when each image is printed on a photographic printing paper by a printer, an information such as exposure conditions for each image frame, which has been determined taking the above-described conditions for photographing, the compensation value, and the like into consideration, are recorded on the processing laboratory tracks. When a reprint is ordered, the recorded exposure conditions, etc., are read out so as to carry out a printing process under the same conditions of an original print.
The recording of information on the magnetic recording section is carried out in accordance with a so-called tri-bit method using two kinds of signals. In this tri-bit method, two kinds of signals corresponding to xe2x80x9c0xe2x80x9d and xe2x80x9c1xe2x80x9d are combined to form a signal for writing the information (hereinafter referred to as a xe2x80x9crecording signalxe2x80x9d) of the date and time of photographing, the place of photographing, the conditions for photographing or the like of each image, or of exposure conditions or the like for each image frame. The signal is supplied to a magnetic head provided in a camera or a photographic printer. Such information is magnetically recorded on the camera tracks or the processing laboratory tracks by the magnetic head on the basis of the recording signal.
As shown in FIG. 11A, a recording signal corresponding to an information to be magnetically recorded on camera tracks is supplied to the magnetic head when the leading ends of the camera tracks C1 and C2 of a transported photographic negative film reach the magnetic head, and the supply of the recording signal is stopped when the recording of the information on the camera tracks C1 and C2 has been completed. Due to occurrence of chattering when the supply of the recording signal is started and stopped, noise often mixes into the recording signal between adjacent camera tracks. Also, when the processing laboratory tracks undergo an overwrite operation, the start code or end code of a previously recorded recording signal sometimes remains unerased. Accordingly, when the information magnetically recorded on the camera tracks is played back in the photographic printer, the noise is mixed in playback signals X1 and X2 of non-recording areas of the camera tracks, as shown in FIG. 11B. This makes it difficult to discriminate signals Y1, Y2, and Y3 read out from the camera tracks C1 and C2 from the mixed noise. This deteriorates the readability of information recorded on the camera tracks. The same problems occur when the information recorded on the processing laboratory tracks is played back.
The present invention has been accomplished to solve the above-described problems, and its object is to provide an information recording method and an apparatus for preventing a magnetically recording portion of a photographic negative film from mixing noise and improving consequently the readability of magnetically recorded information on a magnetic track,
According to a first aspect of the present invention, there is provided an information recording method which includes the steps of causing relative movement between a photographic negative film provided with a magnetic track and a magnetic head, supplying the magnetic head with a signal corresponding to an information to be magnetically recorded so as to magnetically record the information in a first predetermined region of the magnetic track, recording the information on the first predetermined region of the magnetic track of the photographic negative film on the basis of the signal supplied to the magnetic head, supplying the magnetic head with one of direct current and alternating current when the magnetic head is located at a second predetermined region which is outside the first predetermined region, and operating the one of the direct current and the alternating current to the second predetermined region of the photographic negative film through the magnetic head.
According to a second aspect of the present invention, the frequency of the alternating current is more than 5 times the maximum frequency of the signal.
According to the third aspect of the present invention, the magnitude of the direct current is substantially equal to an optimal recording current of the magnetic head.
According to the fourth aspect of the present invention, there is provided an information recording apparatus which includes a magnetic head, moving means for causing relative movement between the magnetic head and a photographic negative film, and supplying means adapted to operate when the relative movement between the magnetic head and the photographic negative film having a magnetic track is being effected, so as to supply the magnetic head with a signal corresponding to information to be magnetically recorded when the magnetic head is located in a first predetermined region of the magnetic track on the photographic negative film to record the information on the first predetermined region of the magnetic track of the photographic negative film on the basis of the signal supplied to the magnetic head, and so as to supply the magnetic head with direct current or alternating current when the magnetic head is located outside the predetermined region of the magnetic track to operate the one of the direct current and the alternating current to the second predetermined region of the photographic negative film through the magnetic head.
In the first aspect, the relative movement is caused between the photographic negative film provided with the magnetic track and the magnetic head. Such relative movement between the photographic negative film and the magnetic head may be caused by moving both the photographic negative film and the magnetic head. Also, such relative movement may be obtained by moving the photographic negative film relative to the magnetic head which is maintained stationary. Moreover, such relative movement may be obtained by moving the magnetic head relative to the photographic negative film which is maintained stationary. While the relative movement between the photographic negative film and the magnetic head is continued, the signal corresponding to the information to be magnetically recorded is supplied to the magnetic head so as to magnetically record the information in a first predetermined region of the magnetic track. Also, one of the direct current and the alternating current is supplied to the magnetic head when the magnetic head is located at a second predetermined region which is outside the first predetermined region.
In the second aspect, the magnetic head is supplied with the alternating current having a frequency more than 5 times the maximum frequency of the signal corresponding to the information to be magnetically recorded when the magnetic head is located at the second predetermined region outside the first predetermined region.
In the third aspect, the magnetic head is supplied with the direct current having a magnitude substantially equal to an optimal recording current of the magnetic head when the magnetic head is located at the second predetermined region outside the first predetermined region.
In the fourth aspect, the moving means causes relative movement between the magnetic head and the photographic negative film provided with the magnetic track. The relative movement between the photographic negative film and the magnetic head can be caused in the above-described manner. In the state in which such relative movement is being continued between the magnetic head and the photographic negative film provided with the magnetic track, the supply means supplies the magnetic head with the signal corresponding to the information to be magnetically recorded when the magnetic head is located in the first predetermined region of the magnetic track on the photographic negative film. The magnetic head magnetically records the information corresponding to the signal in the predetermined region. Also, the supply means operates in the above-described state to supply the magnetic head with one of the direct current and the alternating current when the magnetic head is located at the second predetermined region outside the first predetermined region of the magnetic track.
As described above, one of the direct current and the alternating current is supplied to the magnetic head when the magnetic head is located at the second predetermined region outside the first predetermined region of the magnetic track on the photographic negative film. Accordingly, invasion of noise is prevented, and a signal corresponding to a recorded information is prevented from remaining on the magnetic track, thereby improving the readability of the information magnetically recorded on the magnetic track.